{"hq_id":"hq-p-hom-000169","name":"Asphalt Roofing Shingles (PAH Exposure During Installation and Weathering)","category":{"primary":"household","secondary":"construction","tags":["asphalt shingle","PAH","roofing","installation","weathering","runoff"]},"product_tier":"HOM","overall_risk_level":"moderate","description":"Asphalt roofing shingles containing oxidized bitumen, fiberglass mat, and mineral granules. Installation workers exposed to PAHs from heated asphalt and shingle dust. Pre-1980 shingles may contain asbestos. Weathering releases PAH-containing microparticles into stormwater runoff — documented source of urban waterway PAH contamination. Coal tar sealant (used on driveways adjacent to roofs) contains 50,000 ppm PAHs vs 50-100 ppm in asphalt shingles.","synthesis":{"derived_risk_level":"moderate","synthesis_confidence":0.747,"synthesis_method":"compound_composition","context_used":"human_adult","context_source":"product_users","exposure_modifier":0.77,"vulnerability_escalated":false,"escalation_reason":null,"compounds_resolved":2,"compounds_total":2,"synthesis_date":"2026-05-09","synthesis_version":"1.2.0","methodology_note":"exposure_modifier and adjusted_magnitude are computed from ALETHEIA-calibrated heuristics (route × duration × frequency multipliers, clamped to [0.5, 1.4]). Multipliers are directionally informed by EPA Exposure Factors Handbook (2011) and CalEPA OEHHA but are not regulatory consensus. See /api/methodology for full disclosure."},"hazard_summary":{"sensitive_populations":"roofing workers (occupational PAH), aquatic ecosystems (stormwater)","overall_risk":"moderate","primary_concerns":["Occupational PAH exposure during installation (heated asphalt fumes)","Pre-1980 shingles may contain asbestos (removal hazard)","Stormwater runoff containing PAH-laden microparticles (environmental)"],"exposure_routes":"Occupational: inhalation/dermal during installation. Consumer: negligible. Environment: stormwater."},"exposure":{"routes":["inhalation","dermal"],"contact_types":["inhalation","skin_brief"],"users":["adult","occupational"],"duration":"hours","frequency":"rarely","scenarios":["Roofing installation: PAH inhalation from heated shingles (occupational)","Pre-1980 shingle removal: asbestos fiber exposure risk","Consumer: minimal direct exposure from installed roof","Environmental: stormwater PAH runoff from weathered shingles"],"notes":"Consumer exposure from installed roof is negligible. Risk is concentrated in: (1) installation workers, (2) pre-1980 asbestos shingle removal, and (3) environmental stormwater runoff. USGS: asphalt shingle runoff is a significant urban PAH source. Roofers have elevated urinary PAH metabolites during installation."},"consumer_guidance":{"usage_warning":"Consumer exposure from installed shingles is negligible. If re-roofing pre-1980 home: test shingles for asbestos before removal. Hire licensed abatement if asbestos present. Do not burn old shingles.","safer_alternatives":["Metal roofing (zero PAH, recyclable, longest lifespan)","Clay or concrete tile (inert, no organic compounds)","Synthetic slate (recycled polymer, no asphalt)"],"red_flags":[{"indicator":"Aging infrastructure without inspection or testing","meaning":"Degradation increases contamination risk over time.","action":"Test or inspect per recommended schedule."}],"green_flags":[{"indicator":"NSF or third-party certification","meaning":"Independent testing for safety standards.","verification":"Check for NSF, UL, or equivalent certification marks."}],"what_to_ask":[{"question":"What certifications does this product or system carry?","why_it_matters":"Certification verifies compliance with health-based standards.","good_answer":"NSF, UL, or equivalent third-party certification.","bad_answer":"No certification or self-certified."}],"alternatives":[{"name":"Metal roofing","notes":"zero PAH, recyclable, longest lifespan"},{"name":"Clay or concrete tile","notes":"inert, no organic compounds"},{"name":"Synthetic slate","notes":"recycled polymer, no asphalt"}]},"regulatory":{"applicable_regulations":[{"jurisdiction":"USA","regulation":"OSHA Construction Standards (29 CFR 1926)","citation":"29 CFR 1926","requirements":"Fall protection and PPE requirements for roofing work. No specific PEL for asphalt roofing fumes.","compliance_status":null,"effective_date":null,"enforcing_agency":"OSHA","penalties":null,"source_ref":null}],"certifications":[],"labeling":{"required_disclosures":[],"prop65_warning":{"required":null,"chemicals":[],"endpoint":null,"notes":null},"ghs_labeling":{"required":null,"signal_word":null,"pictograms":[],"hazard_statements":[],"notes":null},"hidden_ingredients":{"trade_secret_protected":null,"categories_hidden":[],"estimated_count":null,"known_concerns":null,"notes":null},"notes":null},"recalls":[],"regulatory_gap":null,"notes":null},"lifecycle":{"recyclable":true,"disposal_guidance":"Shingle recycling where available (asphalt repaving). Pre-1980: test for asbestos before disposal.","hazardous_waste":false,"expected_lifespan":"20-30_years"},"formulation":{"form":"varies","key_ingredients":[{"hq_id":"hq-c-org-000029","name":"Benzo[a]pyrene","role":"bitumen_component","concentration_pct":"1-100 ppm"},{"hq_id":"hq-c-org-000096","name":"Naphthalene","role":"bitumen_component","concentration_pct":"5-50 ppm"}],"certifications":[]},"materials":{"common":[],"concerning":[],"preferred":[]},"compound_composition":[{"hq_id":"hq-c-org-000029","compound_name":null,"role":"bitumen_component","typical_concentration":"1-100 ppm"},{"hq_id":"hq-c-org-000096","compound_name":null,"role":"bitumen_component","typical_concentration":"5-50 ppm"}],"identifiers":{"common_names":["asphalt roofing shingles (pah exposure during installation and weathering)"],"aliases":[],"manufacturer":null,"brands":[]},"brand_examples":[{"brand":"DAP","manufacturer":"DAP","market_position":"mass_market","notable":"Leading caulk and sealant brand"},{"brand":"GE Silicone","manufacturer":"Momentive","market_position":"mass_market","notable":"Silicone sealant brand"},{"brand":"Red Devil","manufacturer":"Red Devil","market_position":"mass_market","notable":"Budget caulk and sealant"}],"brand_examples_disclaimer":"Representative branded products of this category. Concerning ingredients listed in materials.concerning[] apply to the category, not necessarily to every named brand. Specific formulations vary by SKU and may have changed since this record was written; consult the brand's current ingredient label before drawing brand-level conclusions.","sources":[{"type":"expert_curation","name":"ALETHEIA Safety Database","date":"2026-03-25"},{"type":"regulation","title":"OSHA Construction Standards (29 CFR 1926)","jurisdiction":"USA","citation":"29 CFR 1926","id":"src_3f3e310d"},{"id":"iarc_100f_bap","type":"regulatory","title":"IARC Monographs Volume 100F: Benzo[a]pyrene — Chemical Agents and Related Occupations","year":2012,"inherited_from_compound":"hq-c-org-000029"},{"id":"epa_bap_iris","type":"regulatory","title":"US EPA IRIS: Benzo[a]pyrene — Toxicological Review (Final)","year":2017,"inherited_from_compound":"hq-c-org-000029"},{"id":"iarc_82_naphthalene","type":"regulatory","title":"IARC Monographs Volume 82: Some Traditional Herbal Medicines, Some Mycotoxins, Naphthalene and Styrene — Naphthalene Group 2B Evaluation","year":2002,"inherited_from_compound":"hq-c-org-000096"},{"id":"epa_iris_naphthalene","type":"regulatory","title":"US EPA: Naphthalene — IRIS Toxicological Review, Carcinogenicity Assessment and Reference Concentrations (Group C)","year":1998,"inherited_from_compound":"hq-c-org-000096"}],"meta":{"schema_version":"4.0.0","last_updated":"2026-03-25","timestamp":"2026-05-14T01:24:40.971Z"}}